Method and apparatus for controlling access to storage media

ABSTRACT

In embodiments, a method and apparatus for controlling access to a storage medium, such as an optically readable medium. Light sensitive or other materials that are adapted to change state and affect reading of a storage medium are used to control access to data that may be stored on optical medium and/or to control use of the medium.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation application of U.S. patent application Ser. No.11/238,580, filed Sep. 29, 2005, U.S. patent application Ser. No.11/005,257, filed Dec. 6, 2004, which is a continuation-in-part of U.S.patent application Ser. No. 10/645,078, filed Aug. 21, 2003, which is acontinuation of U.S. patent application Ser. No. 09/631,585, filed Aug.3, 2000, the contents of which are incorporated herein by reference intheir entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to controlling access to storage media,such as data recorded on optical media.

2. Description of the Related Art

Optically readable storage media, such as music and software CD's andvideo DVD's, provide inexpensive ways to share and disseminate digitalinformation, making such media the media of choice among both producersand consumers. This is clearly evident as CDs have nearly replacedcassette tapes and floppy disks in the music and software industries andDVDs have made significant inroads in replacing video cassette tapes inthe home video industry. Because of the high demand for such opticalmedia and because of the ease and low cost of reproduction,counterfeiting has become prevalent.

A variety of copy protection techniques and devices have been developedto limit the unauthorized copying of optical media. Among thesetechniques are analog Colorstripe Protection System (CPS), CGMS, ContentScrambling System (CSS) and Digital Copy Protection System (DCPS).Analog CPS (also known as Macrovision) provides a method for protectingvideotapes as well as DVDs. The implementation of Analog CPS, however,may require the installation of circuitry in every player used to readthe media. Typically, when a disk or tape is “Macrovision Protected,”the electronic circuit sends a colorburst signal to the composite videoand s-video outputs of the player resulting in imperfect copies. The useof Macrovision may also adversely affect normal playback quality.

With CGMS, the media may contain information dictating whether or notthe contents of the media can be copied. The device that is being usedto copy the media must be equipped to recognize the CGMS signal and alsomust respect the signal in order to prevent copying. The ContentScrambling System (CSS) may provide an encryption technique that isdesigned to prevent direct, bit-to-bit copying. Each disk player thatincorporates CSS is provided with one of four hundred keys that allowthe player to read the data on the media, but prevents the copying ofthe keys needed to decrypt the data. However, the CSS algorithm has beenbroken and has been disseminated over the Internet, allowingunscrupulous copyists to produce copies of encrypted disks.

The Digital Copy Protection System (DCPS) provides a method wherebydevices that are capable of copying digital media may only copy disksthat are marked as copyable. Thus, the disk itself may be designated asuncopyable. However, for the system to be useful, the copying devicemust include the software that respects the “no copy” designation.

Each of these copy protection techniques, and others that may beavailable, may make it more difficult to copy material from opticalmedia, and may deter the casual copyist. However, these techniques maybe easily circumvented by the unscrupulous copyist who is intent onmaking digital copies of a disk.

In addition to directly copying content from optical media, producersand distributors of digital content are also adversely affected byunauthorized distribution of content over communications systems, suchas the Internet. Known copy protection systems may not be capable ofprotecting a digital data file from being duplicated if it isintercepted by a copyist during transmission over these communicationsystems.

SUMMARY OF THE INVENTION

Embodiments of the invention enable control of access to storage media,such as optical disks. A material may be provided on the media that isalterable between at least two states, wherein at least one of thestates affects whether or how data is read from the media. The materialmay represent information, such as a conventional barcode representsinformation on a package, or an encryption decryption key, or thepresence of the material alone may allow access to the media. Thematerial may prevent reading data from a medium, or alter a result ofreading data from a medium, e.g., while the material is in one state adata bit “1” may be read, but while the material is in another state adata bit of “0” may be read. The material may be permanent to allowauthorized access to the medium for its normal expected lifetime, ortemporary such that the material prevents access to the medium when itis no longer detectable after a certain amount of time or a number ofreads of the medium.

Aspects of the invention may also provide for secure downloads of dataas well as provide for “uncopyable copies” of data that has beenlegitimately downloaded from a source. Aspects of the invention may beused to limit the number of times software may be installed or thelocation of the installation of software. The material may be used toprovide dynamic watermarking of data, or used to uniquely identify aspecific storage medium.

In another aspect of the invention; an optical media may include a lightsensitive material that is positioned in or on the medium so that itprovides a code that may be required to install software from the mediumonto a computer. For example, the code provided by the pattern of lightsensitive material on the medium may be required to match a code that isinput by the user of the medium in order for the software contained onthe medium to be properly installed.

In another aspect of the invention, a particular medium, for example aCD or a DVD, may be provided with an invisible authentication mark orcode in the form of a pattern of light sensitive material. The patternof light sensitive material that has been placed in or on the medium maybe verified by an optical reader prior to allowing the medium to be usedfor either reading or recording digital data. The medium may include,for example, a phosphorescent dye placed in or on the surface of themedium, and the material may not respond instantaneously to excitationby light of a particular wavelength. However, the material may provide adelayed, persistent response that can be detected upon a later reading.

In another aspect of the invention, an optical medium, for example a CDor a DVD, is provided with a data track that is recorded onto the mediumusing a temporary light sensitive material. The temporary lightsensitive material may allow for a limited number of uses of the datacontained in the medium prior to its fading and providing inadequatedata to allow the medium to function as originally intended.

In another aspect of the present invention, software may be distributedon a medium that includes a light sensitive material that provides acode allowing the user of the medium to access a portion of the datacontained on the medium. For example, the medium may include a versionof software that can be freely used and copied to other recordingdevices. However, to access an advanced program recorded on the medium,a code represented by the pattern of light sensitive material containedin or on the medium must first be detected on the medium itself.

In another aspect of the invention, an optical medium containing apattern of light sensitive material may be placed in a reader attachedto a computer where the pattern of light sensitive material may bedetected. A data file, for example a movie or audio file, may then bedownloaded from a network to the computer in a form that is unplayablein the absence of the code provided by the light sensitive material onthe medium. This may allow for the download of digital files such asmovies, over the Internet, that result in playable copies only whenrecorded onto media that contain the proper sequence of light sensitivematerial in or on the medium. The system may, for example, prevent thedownloading of a digital data file without a properly encoded disk, orin another embodiment, may result in an unplayable copy if notdownloaded onto an appropriate disk.

In one embodiment, optical media may include a light sensitive materialin addition to any recording layer, such as a data track. The recordinglayer may be used to record data that may be read from the media toperform a function for which the media is distributed. For example, themedia may include a software program recorded on a data track to be usedwith a personal computer. The light sensitive material may be placed inone or more loci on the media and may or may not represent data that isread from the media when the software is installed.

In another embodiment, the light sensitive material may be used tocomplete an incomplete data set. For example, a data file may berecorded on a medium so that it includes less than what is necessary tomake the data file operable. Enough data may be missing so that errorcorrection techniques may be ineffective. However, the missing data maybe provided in the form of, for example, a light sensitive materialstrategically placed on the medium or on a companion medium. Both datasets may then be combined to result in an operable disk. The entireprocess may be transparent to the user. Instructions for reading themissing data may be provided, for example, in software contained on themedium, in firmware, in hardware or in instructions provided by theuser. Thus, any copy of the medium may be inoperable absent either thestrategically placed light sensitive material or the instructions on howto access the light sensitive material.

In another embodiment, access, copying and unauthorized installation ofdigital data may be prevented by placing light sensitive material in thelight path of the reader so that the light sensitive compound interfereswith the reading of the underlying data. For example, instructionsprovided to authorized users of a software program may instruct aninstallation program to read a specific track and then to wait aspecified time to access an adjacent track. Absent these instructions, alight sensitive material will have been activated upon reading the firsttrack and will interfere with the reading of adjacent, or nearby,tracks, for a period of time equal to the time of persistence of thelight sensitive material. Thus, authentic reading or installationinstructions will provide a map for avoiding these traps. Areas of lightsensitive material may be large enough to defeat sophisticatederror-correction programs, such as EFM and parity bit correctiontechniques known to those of skill in the art.

The light sensitive material may be placed at a position or a number ofpositions on the optical medium in order to provide, for example,identification, verification, an access code or additional data. In oneembodiment, the light emissive compound may be deposited in or on theoptical medium in order to identify the medium or supply informationabout it, much like a bar code may be used to identify a product orpackage. For example, the medium may be theoretically divided into anumber of sectors, for instance, 20 pie shaped pieces of equal sizearound a circular optical recording medium such as a CD-ROM or DVD.Depending on where light sensitive material is placed in each of thesesectors, digital data may be represented by either the absence orpresence of light sensitive material at different locations in eachsector. Sampling instructions may be supplied through a number ofchannels. For example, instructions may be supplied on the mediumitself, by the optical reader or by the user of the device. The samplinginstructions may direct the reader to sample various locations withineach sector looking for the presence or absence of light sensitivematerial. In addition, the reader may be instructed to sample at aspecific time delay or to look for a shift in wavelength from thatprovided by the light source. Thus, each sector may provide informationthat may not be detected unless specifics such as position, wavelength,time of delay and persistence of the light sensitive material are known.A number of different materials having different characteristics may beused on a single medium to provide a more sophisticated codingtechnique.

Light sensitive material may be placed on a medium in a pattern thatprovides a code to unlock access to data stored on the medium, orelsewhere, such as from an attached data storage device. Thus, the codedoptical medium may be used as an uncopyable key to provide access todata, files and information. The light sensitive material may be placedon the medium so that, upon reading, a unique data string is producedthat allows the data files to be opened. The data string may be afunction of, for example, emission, absorption, wavelength shift, timedelay, persistence or intensity of the light sensitive material. Thus, awide variety of variables may be used with a single medium to provide asophisticated code. For example, an unscrupulous copyist may try todecode a medium by determining where on the medium delayed emissioncompounds have been placed. However, other variables such as absorbingcompounds, compounds exhibiting different persistence, and compoundsemitting at different intensities may be used to further thwart thecopyist. Alternatively, the code may be simple, such as the placement ofa single spot of light sensitive material on the medium.

These and other aspects of the invention will be apparent from thefollowing description.

BRIEF DESCRIPTIONS OF DRAWINGS

The invention is described, by way of example, with reference to theaccompanying drawings, in which:

FIG. 1 is a schematic block diagram of a system that may be used withthe present invention;

FIG. 2 shows an optical medium having light sensitive materialpositioned in or on the medium; and

FIG. 3 shows a portion of an optical medium having a spot of lightsensitive material associated with four data tracks.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to controlling access to a storage medium,such as an optical disk. Aspects of the invention provide for copyprotection as well as identification and use, such as writing data, of astorage medium, and/or encryption, distribution protection, or other useof data associated with a storage medium. For example, one aspect of theinvention provides a method and apparatus for preventing theunauthorized reproduction of data recorded on an optical medium as wellas limiting the distribution of data that may be distributed over acommunications system, such as the Internet. Aspects of the inventionmay be practiced without alterations to readers and writers that arecurrently used with optical media such as CD-ROMs, Audio CDs, MO disks,and DVDs.

As one example, a CD may include a light sensitive material that ispositioned in one or more positions on the CD. The light sensitivematerial may be alterable between two states, such as transparent andlight emitting, to affect reading of data from the CD. The lightsensitive material may be caused to change from a first state to asecond state by being illuminated, such as by laser light from a CDreader, and then change from the second state to the first state withoutbeing illuminated. The light sensitive material may have some delay timebetween being illuminated and actually changing from the first to secondstate, e.g., changing from transparent to light emitting, so that datamay be read from the CD before the light sensitive material changes tothe second state. Thus, the delay time of the light sensitive materialmay be made longer than the read time (including oversampling) for aportion of the CD. Once the light sensitive material has changed to thesecond state, the material may remain in the second state, or have somepersistence, for some time period, e.g., may remain light emitting for 1ms or more. While the material is in the second state, the material mayaffect whether and how the CD is read, e.g., the material in the lightemitting state may cause the reader to output a string of “0”s ratherthan output actual data positioned on the CD below the material, or maycause the reader to be unable to read the CD.

The light sensitive material may be used to verify that the CD isauthentic, e.g., was obtained from a particular source and/or includesdata authorized for particular use. For example, detection of the lightsensitive material adjusting from a first transparent state to a secondlight emitting state after being exposed to light, such as laser lightfrom a CD reader, may be used to perform an authentication test on theCD. The authentication test may include initially scanning the CD forlight emitting regions (which are not found initially since the lightsensitive material had not been exposed to light cause a change instate) followed by a subsequent scan for light emitting regions (whichresults in locating at least one light emitting region of lightsensitive material that changed state in response to being exposed tolight in the initial scan). Identifying a region of the CD that did notexhibit light emitting portion during an initial scan followed byidentification of a light emitting portion in the region during asubsequent scan may be used to determine that the CD is authentic.

The above is only one illustrative example of one aspect of theinvention, and other aspects of the invention are described below. Forexample, the light sensitive material may be alterable between statesother than transparent and light emitting, such as invisible andvisible, light transmissive and light absorbing, light emitting andnon-emitting, and so on. The light sensitive material may be positionedon an optical medium to provide information, such as a code (like abarcode), actual readable data, and so on, or prevent sequential accessto data on the medium, rather than only being detectable within specificregions. Thus, the light sensitive material may be used as part of adata encryption, watermarking or other protection scheme, in addition toproviding an authentication feature.

“Optical Recording Medium” refers to a medium capable of recordingdigital data that may be read by an optical reader.

“Light sensitive Material” refers to a material that is alterablebetween at least two states when irradiated with light.

“Authentication Material” refers to a material used to authenticate,identify or protect an optical medium. The data recorded on an opticalmedium, for example, software, video or audio files, are notauthentication material.

“Temporary Material” refers to material that is detectable for a limitedamount of time or a limited number of readings.

“Re-read” refers to reading a portion of the data recorded on a mediumafter it has been initially read.

“Fluorescent Compound” refers to a compound that radiates light inresponse to excitation by electromagnetic radiation.

“Phosphorescent Compound” refers to a compound that emits light inresponse to excitation by electromagnetic radiation wherein the emissionis persistent over a length of time.

“Recording Layer” refers to a section of an optical medium where data isrecorded for reading, playing or uploading to a computer. Such data mayinclude software programs, software data, audio files and video files.

“Recording Dye” refers to a chemical compound that may be used with anoptical recording medium to record digital data on the recording layer.

“Security Dye” refers to a compound that may provide or alter a signalto protect the data on a storage medium.

“Non-Destructive Security Dye” refers to a security dye that does notrender media permanently unreadable.

“Reader” refers to any device capable of detecting data that has beenrecorded on an optical medium. Examples are CD and DVD readers.

“Communication System” refers to any system or network for transferringdigital data from a source to a target.

FIG. 1 is a schematic block diagram of a system 100 that may be usedwith various aspects of the invention. In this illustrative embodiment,the system 100 includes a data processing apparatus 1, which may be ageneral purpose computer, or network of general purpose computers, andother associated devices, including communications devices, modems,and/or other circuitry or components necessary to perform the desiredinput/output or other functions. The data processing apparatus 1 canalso be implemented, at least in part, as a single special purposeintegrated circuit (e.g., ASIC) or an array of ASICs, each having a mainor central processor section for overall, system-level control, andseparate sections dedicated to performing various different specificcomputations, functions and other processes under the control of thecentral processor section. The data processing apparatus 1 can also beimplemented using a plurality of separate dedicated programmableintegrated or other electronic circuits or devices, e.g., hard wiredelectronic or logic circuits, such as discrete element circuits orprogrammable logic devices, and can also include any other components ordevices, such as user input/output devices, a keyboard, a user pointingdevice, touch screen, etc.

The data processing apparatus 1 may communicate with a media reader 2,which may be a conventional CD, DVD or other optical media reader.Optical media, which may include one or more aspects of the inventionmay be read by the media reader 2, and information regarding the readingprovided to the data processing apparatus 1. The data processingapparatus 1 may also communicate with a display 3 that provides arepresentation of the data read by and provided from the media reader 2.The display 3 may be a computer monitor, a CRT or LCD display, one ormore audio speakers, a printer, or any other device or combination ofsuitable devices. As one example, the data processing apparatus 1, themedia reader 2 and the display 3 may all be incorporated into a singleDVD player, such that a user can have a DVD read and played back usingthe display 3.

The data processing apparatus 1 may also communicate with a dataprovider 5 or any other device through a communication system 4, such asthe Internet, a wired or wireless telecommunications network, aninfrared communication system, and the like. The data provider 5 mayinclude a general purpose computer, or network of computers, or otherdevices capable of communicating with the data processing apparatus 1.

FIG. 2 shows a schematic diagram of an optical medium 20 in anillustrative embodiment of the invention. In this embodiment, the medium20 includes a light sensitive material 21 that is positioned on themedium 20 in three different locations or spots. Although in thisembodiment the material 21 is positioned in three different locations,the light sensitive material 21 may be placed on or in the medium 20 inany number of ways. In one embodiment, the entire medium 20 or onesurface of the medium 20 may be coated with light sensitive material 21.In other embodiments, the material 21 is positioned at a number ofdiscrete predetermined locations or in a random fashion. The lightsensitive material 21 may be positioned so that it is located winprecisely defined boundaries, or so that it is merely located roughlywithin a specified area The shape and size of the areas of the medium 20including light sensitive material 21 may not be important, as anyunderlying data may not be affected by the light sensitive material 21.

The light sensitive material 21 may be placed so that it lies in anoptical read path of the media reader 2 so that the light sensitivematerial 21 is irradiated by light when the data is read. Alternately,the light sensitive material 21 may be placed in an area of the medium20 that is not designed to hold recorded data or that includes dummydata that may not be required for use of other data on the medium 20. Itshould be understood, however, that the medium 20 need not include anydata, but instead may be a “blank” medium 20 that can be written withdesired data.

The light sensitive material 21 may be placed at any depth within themedium 20 between and including the surface of the medium 20 and anunderlying data layer. For example, the light sensitive material 21 maybe placed on the surface of the medium 20 through which light passes toread the underlying data In another embodiment, the light sensitivematerial 21 is placed close to the recording layer of the medium 20 sothat the focal distance to the light sensitive material 21 is similar tothat of the recording layer. In another embodiment, the light sensitivematerial 21 is placed on the surface of the medium 20 and is then coatedwith a protective layer.

In addition to the size and shape of the placement, other factors maydetermine how a light sensitive material 21 may be illuminated to anextent great enough to change state. For example, the depth of theplacement of the light sensitive material 21 within the medium 20 may bea factor in determining when a light source will be properly positionedto illuminate the material 21 to an extent necessary to provide adetectable response, i.e., change in state. For example, ifpolycarbonate is used as a substrate material of the medium 20, thepolycarbonate substrate may act as a lens to focus a light beam so thatthe beam becomes more focused at locations closer to the underlying datatrack than near the surface of the polycarbonate opposite the datatrack. Therefore, an equally sized and shaped placement of lightsensitive material 21 near the surface of the medium 20 may beilluminated during reading of a broader range of underlying addressabledata points than would be if the light sensitive material 21 werepositioned in the substrate closer to the data track or the focal pointof the light source. This may occur because the light beam is broaderand less focused, covering more area, when it strikes the surface of themedium opposite the data layer, rather than when it is focused near thedata layer. This may also result in a lower beam intensity at thesurface of the medium than at the data layer and, accordingly, lightsensitive material 21 placed close to the surface of the medium may bemade denser or more sensitive in order to provide an adequate response.

The light sensitive material 21 may be positioned in or on the medium 20by any number of methods including direct application, spin coating,molding the light sensitive material 21 into a substrate of the medium20, and dispersing the light sensitive material 21 in a second materialthat is compatible with the medium 20 substrate. For example, the lightsensitive material 21 may be dispersed in a prepolymer of polycarbonate,PVC or vinyl acetate and then fixed in a suitable pattern on the medium20. The chosen light sensitive material 21 may exhibit long termstability under typical optical media storage conditions and may belight fast and non-reactive. In addition, materials 21 may be chosenbased on compatibility with the polymer or other material that is usedto produce a substrate for the medium 20. The light sensitive material21 may be included with the medium 20 before, during or after data hasbeen written or otherwise provided on the medium 20.

The light sensitive material 21 may be any material that is affected bylight, for example by becoming reflecting, absorbing or emitting whenilluminated by a light source. The light source may be a data readinglight, such as a media reader 2 laser or other light source. The lightsensitive material 21 may change between two or more states. Forexample, the material 21 may be alterable between emissive andnon-emissive states, absorbent and non-absorbent states, or reflectiveand non-reflective states. The material 21 may alter states when excitedby a light source, such as a laser, and later change states again withor without any further illumination. Thus, the light sensitive material21 may change from a first state to a second state after illumination,and later change from the second state to the first state without beingilluminated again.

The light sensitive material 21 may also have a delay in its change fromone state to another after being illuminated. For example, the material21 may be non-emissive for a delay period after excitation by a lightsource and then may become light emissive after the delay. For example,the material 21 may be light absorbent upon illumination, and after adelay period become light emissive. In another embodiment, the lightsensitive material 21 may emit light at one wavelength in a first stateand then, after additional excitation, emit light of a differentwavelength in a second state.

The light sensitive material 21 may have persistence, e.g., a timeperiod during which the light sensitive material 21 remains in analtered state (e.g., light emitting) before changing to another state(e.g., transparent) absent sufficient illumination or other excitationwhile in the altered state. The persistence may vary widely, e.g., from1 nanosecond to 1 minute or more. For example, a light sensitivematerial 21 may switch from a first state to a second state after beingilluminated by an appropriate light, and remain in the second state forits persistence time, e.g., 1.6 ms, before changing back to the firststate (absent sufficient illumination or other excitation while in thesecond state).

The medium 20 may include data for digital files, such as data sets,computer programs, sound, images and video. The light sensitivematerials 21 may be applied to the medium so that the presence of thematerials 21 may or may not be detected during an initial reading or ina single read operation using conventional oversampling. If thematerials 21 are chosen so that their presence cannot be detected duringa single read using oversampling, e.g., the delay time is greater thanthe total read time including oversampling, the reader 2 may be directedto reread the same area of the medium 20 a short time after an initialread, and the light sensitive material 21 may have changed states.

Although light of a different wavelength and intensity than that used inconventional optical media readers 2 may be employed to illuminate thelight sensitive material 21, it may be advantageous to used lightsensitive compounds that respond to light sources that are used inconventional readers. In addition, it may be preferable that the lightsensitive compounds are detectable by conventional readers 2. However,the light sensitive material 21 may be replaced with other materialsthat change state when exposed to a signal other than light, such as anelectric or magnetic field, a rise in local temperature, etc. Oneexample may be a material that changes state in response to a rise inlocal temperature, e.g., caused by the reading light of an media reader2 or other heat source, such that the state change can be detected bythe reader 2 light.

Having described some of the ways in which a light sensitive material 21may be provided in association with an optical medium 20, examplesregarding how the light sensitive material 21 may be used in a fewillustrative embodiments are described. It should be understood thatvarious aspects of the invention described above and/or in the followingExamples may be used singly or combined together in various ways in asingle device or application.

EXAMPLE 1

In one illustrative embodiment, the presence of light sensitivematerials 21 on a medium 20 is used to determine that the medium 20 isan authorized medium 20 and/or contains data authorized for a particularuse. In this embodiment, the light sensitive material 21 on the medium20 is used by an installation program to prevent unauthorizedinstallation of software recorded on the medium 20 on a computer, butthe same or similar technique may be used to prevent unauthorized use ofthe medium 20, unauthorized use, such as reading or writing, of data onthe medium 20, and so on. In this example, the installation programalong with data representing the software code are recorded on themedium 20, but the installation program may be provided in other ways,such as stored in a memory of a media reader 2, on another medium 20,etc.

When an attempt is made to install the software on the medium 20 shownin FIG. 2, the installation program is read from the medium 20, e.g., bythe media reader 2, and implemented by the data processing apparatus 1.The installation program includes instructions to verify that thesoftware to be installed is contained within an authorized medium 20.Part of the authentication procedure may involve reading portions of themedium 20 in a defined sequence and/or at a defined timing. The readsequence and timing may be stored as part of the installation program ormay be determined randomly, e.g., by the program using a random numbergenerator. For example, the installation program may direct the mediareader 2 to read portions of the medium 20 within sectors 20 a-20 f inorder during a first read. Depending upon the nature of the lightsensitive material 21, the reader 2 may not detect the presence of thelight sensitive material 21 during the first read, and output a signalrepresenting the read result. The reader 2 may not detect the lightsensitive material 21 if, for example, the delay time of the material 21is longer than the read time for each sector 20 a-20 f. As discussedabove, the light sensitive material 21 may be positioned on the medium20 in association with actual target or useable data, such as portionsof the software program, or in association with dummy data. Thus, thereader 2 may output a signal representing dummy data read from each ofthe sectors 20 a-20 f after the first read. For simplicity and as oneexample, the reader 2 may output a signal “000000”, where each “0”represents the dummy data read from each of the six sectors 20 a-20 fduring the first read.

Next, the installation program may instruct the media reader 2 to againread the sectors 20 a-20 f in that order during a second read. Eachsector 20 a-20 f is to be read at a timing such that the second read ofthe sector 20 a-20 f occurs after a delay time (if any) and within apersistence time for the light sensitive material 21. That way, assumingthe first read of each portion of sector 20 a, 20 c and 20 e wassufficient to illuminate the light sensitive material 21 and cause thematerial to change state, the second read will be performed while thelight sensitive material 21 is in its changed state. Since the lightsensitive material 21 is in its changed state during the second readcycle, the media reader 2 will output a signal representing a read wherethe light sensitive material 21 in its changed state was encountered.For example, the media reader 2 may output a signal “101010” for thesecond read, where the “1”s represent a read where light sensitivematerial 21 in a changed state was encountered in sectors 20 a, 20 c and20 e and the “0”s represent a read dummy data read in sectors 20 b, 20 dand 20 f. Reading of sectors 20 a, 20 c and 20 e during the second cyclemay result in the media reader 2 reading different data than that duringthe first read, e.g., the dummy data under the light sensitive material21 may include a string of “0”s while the light sensitive material 21during the second read cycle may cause the reader 2 to read a string of“1”s. The light sensitive material 21 may have other affects on thereading of the medium 20 during the second read cycle, such as causingthe reader 2 to output an “end of file” signal, a signal indicating thatthe medium 20 is not readable, or some other indication of the lightsensitive material 21 being in an altered state.

By comparing the two signals generated during the first and second readcycles, e.g., determining that the two reads provided different resultsfrom reading the same portions of sectors 20 a-20 f, the installationprogram may determine that the medium 20 is an authentic medium (asopposed to an unauthorized copy) and allow installation of the softwareprogram to continue. Otherwise, the installation program may denyinstallation of the program.

The installation program need not necessarily require a precise matchbetween an expected output from a media reader 2 during anauthentication process and the actual output. Instead, the installationprogram may only require that the actual output from the media reader 2be within a desired range of values. Using a simplified extension of theexample above, light sensitive material 21 may be provided in any one ofthe sectors 20 a-20 f during manufacture, as long as at least one sectorincludes light sensitive material 21. In this case and using the exampleprovided above, the installation program may accept actual output fromthe media reader 2 during the second read cycle between the range“000001” and “111111” are acceptable for authentication purposes.

Since a relatively large area of each sector 20 a-20 f may be readduring authentication, precise positioning of the light sensitivematerial 21 within each sector may not be required. Instead, approximatepositioning may be adequate. In addition, the medium 20 may beconceptually divided into more than, or fewer than, six sectors 20 a-20f, if desired. An increase in the number of sectors may provide a largernumber of possible locations for light sensitive material 21, andtherefore provide a more complicated and robust protection scheme.Further, each medium 20 may have a unique distribution of lightsensitive material 21 in its sectors as compared to other media 20 in agroup. Thus, a unique code may be provided on each medium 20 using thelight sensitive material 21 positioned in different locations.Protection may be further enhanced by varying the delay times and/orpersistence of light sensitive materials 21 positioned on the medium 20.

EXAMPLE 2

Those of skill in the art will appreciate that Example 1 described abovemay be altered in many ways to provide different and/or varying levelsof protection. As a second example, authentic media 20 may be providedwith an alphanumeric security code that is unique to each disk and isprinted on a card accompanying the media 20. At the time ofinstallation, the installation program may request the user to enter thesecurity code. The installation program may then use the code to verifythe authenticity of the medium 20 having the software to be installed.For example, the installation program may use the security code todetermine a sector 20 a-20 f read sequence and/or timing, as anencryption key or password, to determine where on the medium 20 lightsensitive material 21 is positioned, to determine an expected outputfrom the media reader 2 when using a predefined sector read sequence,and so on. Based on this information, the medium 20 may be read, and theoutput from the reader 2 compared to expected output determined based onthe security code.

The security code may alternately be included on the medium 20 based onthe way the light sensitive material 21 is positioned on the medium 20,e.g., in a way similar to a conventional barcode, and/or other featuresof light sensitive material 21 such as a delay time and/or a persistencefor each spot of light sensitive material 21. As one example, theinstallation program could instruct the media reader 2 to initially readthe medium 20 in a way that the presence and location of light sensitivematerial 21 on the medium 20 is determined. If other features of delayand/or persistence of the light sensitive material 21 are used to encodethe security code, the installation program could then read the lightsensitive material 21 locations in various ways to determine the delayand/or persistence of the material 21 and use that additionalinformation to determine a security code and/or authenticate the medium20. For example, the installation program could instruct the mediareader 2 to read each location of light sensitive material 21 usingdifferent read delay times of 1 ms, 10 ms and 100 ms. If a change instate of the light sensitive material 21 is detected after a delay timeof 10 ms, but not after 1 ms and 100 ms, a determination may be madethat the delay time of the light sensitive material 21 is between 1 msand 10 ms, and the persistence is less than 99 ms. This information,along with position information regarding the material 21 location, maybe used to determine/decode a security code, a medium identificationnumber, an alphanumerical sequence or other information provided by thepattern of light sensitive material 21 on the medium 20. Decodedinformation may be used to determine characteristics of the medium 20and compare those characteristics to characteristics sensed during theauthentication process. For example, a decoded medium identificationnumber may be used to determine, e.g., using stored information, thatthe medium 20 should include light sensitive material 21 in specificlocations, and having specific delay times and/or persistence. Thisinformation may be compared to the sensed location, delay time andpersistence values determined during reading of the medium 20. Thecomparison may result in determining that the medium 20 is authentic andauthorized for use (reading, writing, alteration of data on the medium20 and so on), or that use of the medium 20 should be denied.

EXAMPLE 3

In the examples described above, no distinction was made regardingreading specific portions of a medium 20 that is associated with asingle spot of light sensitive material 21. In this illustrativeembodiment of the invention, different portions of a medium 20 that areassociated with a single spot of light sensitive material 21 are read.FIG. 3 shows a portion of the medium 20 and a spot or area of lightsensitive material 21. Although the medium 20 may have a plurality ofregions each associated with a corresponding spot of light sensitivematerial 21, only the reading of a single portion of the medium 20 isdiscussed below for simplicity. In addition, the light sensitivematerial 21 is associated with four tracks a-d in FIG. 3, but lightsensitive material 21 may be placed in or on a medium 20 so that it isassociated with any number of adjacent tracks.

Part of an authentication procedure for the medium 20 may involvereading a plurality of tracks a-d on the medium 20 that are allassociated with a spot of light sensitive material 21. The location ofspots of light sensitive material 21 may be determined as describedabove, e.g., by searching the medium 20 for regions, by referring to alook up table that corresponds a medium identification number withspecific, expected material 21 locations, and so on. Reading of thetracks a-d may be performed for the same or similar purpose as readingportions of the medium 20, such as determining a security code for themedium 20, verifying the presence of light sensitive material 21 on themedium 20 (e.g., in specific locations, and/or having specificproperties such as delay time and persistence), and so on. However, inthis embodiment, if any point along tracks a, b, c or d that areassociated with the light sensitive material 21 are read by a lightsource, the light source, the light sensitive material 21 may be causedto alter state. That is, illumination of any of the tracks a-d forreading may illuminate the light sensitive material 21 and cause it tochange from one state to another. For example, if the reader 2 isdirected to sample a section of track a, and light sensitive material 21is a fluorescent compound having a delay time of 10 ms, then reading oftrack a, b, c or d 10 ms after illumination during the first read mayresult in the reader 2 detecting the presence of the light sensitivematerial 21, since illumination of a portion of the light sensitivematerial 21 may cause the entire spot of the material 21 to changestate.

However, if the response of the light sensitive material 21 isdifferent, e.g., only illuminated portions of the light sensitivematerial 21 change state, the reading of track a may cause only aportion of the light sensitive material 21 associated with an adjacenttrack(s) to change state (in addition to the portion associated withtrack a). This may be caused as a result of the light beam reading tracka covering an area larger than that defined by the target track a, e.g.,the light sensitive material is in a different focal plane that thetrack. Thus, the light beam may illuminate portions of the lightsensitive material 21 that is associated with track b, but not portionsassociated with track c or d. In addition, the light sensitive material21 may be excited by light beams used to aid in tracking as well as thelight beam used for reading data. These additional light beams mayfurther broaden the area of light sensitive material 21 that may beexcited by a single read. As a result, reading of track a, followed byreading of track b after the delay time (if any) and within thepersistence time of the light sensitive material 21 may result in themedia reader 2 detecting that the light sensitive material 21 is in achanged state when reading track b.

As one example, the media reader 2 may be directed to read track a,track b, track d, then track c. Given that the readings occur within anamount of time greater than the delay of the light sensitive material 21and during the persistence time, the reader 2 will read data unaffectedby the material 21 from track a, detect that the light sensitivematerial 21 is in an altered state while reading track b, read dataunaffected by the material 21 from track d, and detect that the material21 is in an altered state while reading track c. Of course, reading oftracks a-d may be performed in any suitable order, and with any delay.The result of the reading may be used as discussed above, toauthenticate the medium 20, to determine a security code, identificationnumber or other information for the medium 20, and so on. In addition,the light sensitive material 21 need not be precisely positioned withrespect to the tracks a-d. In fact, imprecise or random placement of thematerial 21 may be used to create unique patterns of material 21 on eachmedium 20. By including material 21 at multiple spots with lightsensitive material 21, a sophisticated read sequence may be required toaccurately obtain the underlying data. If the proper read sequence isfollowed, the data may be used for its intended purpose. However, if animproper read sequence is used, for example, if the reader simplyproceeds along the tracks in a sequential fashion, the material 21 willinterfere with the reading of the underlying data resulting in aninoperable data set.

As with the other examples described above, the areas of light sensitivematerial 21 may be made large enough to avoid error correctiontechniques, such as EFM, from masking detection of the material 21 in analtered state. For example, to prevent masking of error correctiontechniques, the material 21 may be placed over 50,000 or 100,000adjacent bits of data, or over approximately 2 mm on a conventional CD.Therefore, only when the required read sequence, including appropriatejumps and delays, is implemented will the underlying data be properlyread from the medium 20.

This same feature that one or more tracks may be made unreadable byprevious reading of an adjacent track can be used to prevent serialcopying of data on a medium 20 or copying of data on the medium 20 whilenot using an appropriate reading sequence (which may involve readingdifferent regions at different times to account for the location, delayand/or persistence of light sensitive material 21 on or in the medium20). For example, an entire medium 20 may be coated with a lightsensitive material 21 so that data stored on the medium 20 cannot besequentially read from medium 20 unless a first portion is read, therebycausing the light sensitive material 21 to alter state, and a nextadjacent portion associated with the material 21 that has changed stateis read after the material 21 has reverted back to its unaltered state.Reading of the medium 20 sequentially without appropriate timing mayresult in unusable data being read from the medium 20 caused by themedia reader 2 reading light sensitive material 21 that is in an alteredstate.

Similarly, light sensitive material 21 and data may be positioned instrategic locations on the medium 20 so that the data may only besuccessfully read when the data is accessed using a particular accesssequence. The access sequence may be stored as part of the data on themedium 20 (and possibly encrypted), provided by a user as analphanumeric code, and/or stored/encoded by the location, delay and/orpersistence of the light sensitive material 21 on the medium 20, similarto that described above.

As with the other examples, various combinations of materials 21exhibiting absorbence, emission, and reflectance, for example, may beused. In addition, compounds exhibiting various delay times andpersistence times may be used together to create a more sophisticatedprotection system. If the disk is copied, for example, by bit-to-bitcopying, the light sensitive materials 21 may not be copied, and thusthe copied version of the data will be uninstallable, unreadable orotherwise unusable. This will hold true whether or not the user of theunauthorized copy has access to the user code or owns an authorizedcopy.

EXAMPLE 4

Using another aspect of the invention, optical media 20, such as CDs andDVDs, may be read only for a limited amount of time or a limited numberof readings. For example, the medium 20 may include light sensitivematerial 21 that will fade or otherwise be undetectable after a certainamount of time, e.g., one month, or after a certain number of readings,e.g., after three readings. The light sensitive material 21 may be usedin any of the ways described above, e.g., applied in spots on the medium20 and used to authenticate the medium 20. After the material 21 fadesor is otherwise undetectable, data on the medium 20 will no longer beaccessible. Alternately, the material 21 may be used to encode actualuseable data on the medium 20, e.g., data portions of a DVD movie, andafter the material 21 is no longer detectable, the medium 20 willeffectively be blank or partially so. This type of temporary medium 20may be useful in the movie or software rental industry, because themedium 20 will no longer be useable to the renter after authorized useof the medium 20 and/or its content is complete.

For example, the light sensitive material 21 may be a persistent lightsensitive compound placed at a specific location on the medium 20. Thepersistence of the material 21 may be known to decrease with age, oruse, such that after three plays the persistence decreases from 2 ms toless than 1 ms, for example, at a detectable intensity. Therefore, priorto allowing the medium 20 to be accessed, the location at which thelight sensitive compound 21 has been placed is read and then re-readafter about 1 ms. If a response is detected from the light sensitivematerial 21 upon re-reading, the persistence is still greater than 1 ms,and reading of the data may proceed. If no response from the lightsensitive material 21 is detected, the persistence time has droppedbelow the acceptable level and access to the data is denied. In thismanner, by varying the amount of time from initial read to re-read, thesame medium 20, with the same light sensitive material 21 in the samelocation, may be provided with different useful lifetimes. For instance,data access may be provided or denied based on threshold re-readingtimes of 1.5, 1.0 or 0.5 ms, with 1.5 ms corresponding to a medium 20that is one month old, 1.0 ms corresponding to a medium 20 that is 3months old, and 0.5 ms corresponding to a medium 20 that is a year old.

In addition to providing only a limited number of uses, the medium 20may also incorporate copy and/or access protection techniques, such asthose used in the examples above. For instance, phosphorescent compoundsmay be placed at various points on the medium 20 and persistent readingsmust be detected from these locations prior to proceeding with playingthe disk. In this manner, a copy protected temporary data file capableof only a limited number of uses is provided.

EXAMPLE 5

In another embodiment of the invention, an optical medium 20, such as aCD or DVD, may contain a version, or portion, of a movie, audio file,program or data file that may be freely used and duplicated. Forexample, this may be a demo version of a piece of software or thetrailer of a movie. The optical medium 20 may also contain an accessprotected file which may include, for example, the entire softwareprogram or the full length DVD movie. In order to access the fullversion of the program, movie or audio file, the user must input a codewhich can be obtained from an authorized source and may be specific fora particular optical medium 20. Once the code has been input, the properinstallation sequence or reading sequence may be implemented, e.g., theexpected position and type of light sensitive material 21 on the medium20 verified, and the full version of the data can be accessed. Inaddition to limiting access, the invention may be used to preventcopying in a manner similar to those outlined above. Thus, even after anowner is provided with an access code, additional functional copies maynot be made.

EXAMPLE 6

Another aspect of the invention may allow data files, such as movies,software and music, to be safely transmitted over the Internet andrecorded onto an optical medium 20 where an authorized user may havefull access to the content.

For example, a “blank” optical medium 20 may be provided (either “free”or purchased) with a data recording layer and light sensitive materials21 associated with various portions of the medium 20. The pattern oflight sensitive material 21, for instance, a phosphorescent compound,may be unique to this particular medium 20 or to a small group of media20. A user of the medium 20 can contact a data provider 5 of contentusing a data processing apparatus 1 over a communication system 4, suchas the Internet, and request a particular data set, such as a DVD movieor software. When the user decides to purchase or rent the content, forexample, a movie, a unique code for the medium 20 may be detected by themedia reader 2 that is specific to the pattern of light sensitivematerial 21 on the medium 20. The media reader 2 may determine the codeby reading the medium 20 using read instructions received from theprovider 5, using instructions stored on the medium 20; using a set ofstandard read instructions, and so on. This unique code may then betransmitted to the data provider 5. Alternately, the user could 20provide a code, such as a serial number or other identifier, for themedium 20 by typing the code into the data processing apparatus 1 andsending the code over the communication system 4.

Based on the code, the data provider S may create a protected version ofthe requested data. The protected or encrypted version of the movie maybe inoperable in the form in which it is transmitted from the provider 5to the user. Thus, if the file sent by the provider 5 is interceptedduring transmission, the file will not be useable unless associated withthe appropriate medium 20. Because the code that was transmitted to theprovider 5 provides information about the pattern of light sensitivematerial 21 on the medium 20, the encrypted file that is transmitted maybe uniquely produced to work only on the specific medium 20. Thus, onlywhen the data is recorded onto the unique medium 20 may the file becomeusable. Once the data has been written to the medium 20, it may be usedan unlimited number of times if a permanent data recording technique hasbeen used, or alternatively, a temporary recording surface or lightsensitive material 21, such as that described in Example 4 above, may beused to produce a medium 20 capable of a limited number of plays.

Because the medium 20 may require the presence of light sensitivematerial 21 in particular locations, having a particular delay and/orpersistence to be accessible, byte-to-byte copying of the medium 20 mayresult in an inoperable data file. In this manner, a producer ordistributor of copyrighted material may either charge for the blankmedium 20 or charge for the download and can be confident that only asingle copy of a content will be made and used. In an alternativeembodiment, a medium 20 having a unique code of light sensitive material21 may be used as a key to unlock an encrypted file on another medium 20and the unlocked complete file may be copied onto a second disk thatincludes copy protection features, such as those described above. Inthis way, a single unique disk can be used to download multiple movies,songs or programs allowing for efficient accounting and billing methods.

The light sensitive material 21 may be used in different ways to allowaccess to the data stored on the medium 20. For example, the datatransmitted by the provider 5 may have 1000's of inborn errors that arecorrected by the light sensitive material 21, e.g., when the data iswritten to the medium. That is, the data may be constructed so that theerror portions of the data are written on the medium 20 in portions thatare associated with spots of the light sensitive material 21. Thus,using an appropriate read sequence and/or timing, the material 21 may bealtered in state so that the incorrect data is masked or corrected bythe material 21 during reading. For example, the material 21 may have adelay time that is less than half the total time required to read datafrom the medium using oversampling. This results in the read of thematerial 21 providing corrected data while masking the incorrect data.Of course, the delay time may be longer than a single read time usingoversampling. In this case, the material 21 may have to be altered instate before being read to provide corrected data. In this embodiment,the material 21 may be configured or chosen so that the data may bewritten on the medium 20 without altering the state of the material 21,e.g., the delay time of the material 21 is less than the write time.This way, the data may be written to the medium 20 without interferencefrom the material 21.

Alternately, the material 21 may provide information regarding whichdata portions contain errors and how to correct the errors. For example,before or during reading of the data, the data processing apparatus 1and/or the media reader 2 may identify which areas of the medium 20contain light sensitive material 21 (based on a detected change instate) and cut out data portions located in those areas or otherwiseprocess the incorrect data. By using thousands of spots of material 21arranged in a unique pattern on each medium 20, manual or automaticcorrection of the data in an attempt to make an unauthorized copy may bemade very difficult or impossible.

Another possibility is to store encrypted data on the medium 20 and usea decryption key that is determined based on characteristics of thelight sensitive material 21 on the medium 20 to decrypt the data. Forexample, a pattern of light sensitive material 21 on the medium 20 mayprovide an encryption key when read in a particular way, e.g., in aspecific sequence, at a specific timing and so on. This key can be usedto decrypt the data, e.g., in real time during play back, or authorizeuse of the data on the medium 20.

The material 21 may also provide a watermarking function such thatreading of the data on the medium 20 using an improper accessingsequence, e.g., a sequential copy sequence, may result in including dataread from material 21 in an altered state being included in the copy.This data, which is different from data included in an authorized copy,may provide a kind of watermark that can be used to identify that thecopy is an unauthorized one, and/or the source of the copied data.

A variety of techniques are available for implementing different aspectsof the invention. For instance, the output of underlying data may bealtered by the presence of a light sensitive material. Methods andapparatus to apply a version of this technique, and others, aredescribed in co-owned U.S. patent application Ser. No. 09/608,886, filedJun. 30, 2000, and hereby incorporated herein by reference in itsentirety.

Light sensitive materials 21 have been chosen and described for use inthe examples above, in part, because of the current popularity ofoptical storage media and because they may provide a convenient way ofprotecting stored data without requiring alteration of conventionaloptical media readers. It should be understood, however, that variousaspects of the invention may be extended to use of other types ofmaterials, such as materials that change state or otherwise respond tosignals other than light, or other types of storage media. For example,materials that change state in response to an electric or magnetic fieldmay be used in place of the light sensitive materials 21. The materialsmay be used in media that are optically read, or in media that are readusing other signals. As one example, a material that changes state inresponse to an electric field and effects light in different ways basedon its state, such as a liquid crystal material that changes state inresponse to an electric field and alters the polarization of lightpassing through the material, may be used in place of, or in additionto, the light sensitive materials 21. In such cases, media readers mayhave to be altered to accommodate the different type of material, e.g.,by including a device to create an electric field at desired locationson the medium 20. Thus, the invention is not limited to the use of lightsensitive materials, or to application to optical storage media only.

In addition, in the examples described above, the light sensitivematerials 21 affect reading of a medium 20 after being exposed to lightand changed to an altered state. However, the materials 21 may operateto affect reading of the medium 20 in a first state and not affectreading in a second state. For example, a material 21 may be lightabsorbing prior to being illuminated by an optical reading light. Aftera possible delay time, the material 21 may change state to betransparent such that the material 21 allows reading of data under thematerial 21. After some persistence time, the material 21 may return tothe first absorbing state, thereby preventing reading of data under thematerial. Further, the light sensitive material 21 may affect reading ofdata on the medium in two or more of its states. For example, thematerial 21 may always prevent reading of data under the material 21 aslong as the material 21 is detectable. In a first state, the material 21may cause a reader to read a first data type, such as a “0”, and in asecond altered state may cause the reader to read a second data type,such as a “1”. The material 21 may be temporary such that after anamount of time or a number of readings the material 21 is no longerdetectable, thereby allowing data below the material 21 to be read. Thelight sensitive materials used in the applications discussed above maybe chosen from a group of dyes, specifically, cyanine dyes. Thesecyanine dyes include, among others, indodicarbocyanines (INCY),benzindodicarbocyanines (BINCY), and hybrids that include both an INCYand a BINCY. Hybrids may be, for example, mixtures of two different dyesor, in another embodiment, compounds that include both INCY and BWCYmoieties. In one embodiment, the light sensitive material may be aratiometric compound having a linked structure with excitation ranges atboth the CD and DVD ranges of about 530 and 780 nm. In a furtherembodiment, the dye is phosphorescent, having a time delay of about 10milliseconds and a persistence of several seconds. Table 1 provides someof the dyes that may be useful with some aspects of the invention.

TABLE 1 Dye Name/No. CD/DVD Excitation Emission Alcian Blue DVD 630 nmAbsorbs (Dye 73) Methyl Green DVD 630 nm Absorbs (Dye 79) IndocyanineGreen CD 775 nm 818 nm (Dye 77) Copper Phthalocyanine CD 795 nm Absorbs(Dye 75) IR 140 CD 823 nm(66 ps) 838 nm (Dye 53) IR-768 Perchlorate CD760 nm 786 nm (Dye 54) IR 780 Iodide CD 780 nm 804 nm (Dye 55) IR 780Perchlorate CD 780 nm 804 nm (Dye 56) IR 786 Iodide CD 775 nm 797 nm(Dye 57) IR 768 Perchlorate CD 770 nm 796 nm (Dye 58) IR 792 PerchlorateCD 792 nm 822 nm (Dye 59) 1,1′-dioctadecyl-3,3,3′,3′- DVD 645 nm 665 nmtetramethylindodicarbocyanine perchlorate (Dye 231)1,1′-dioctadecyl-3,3,3′,3′- DVD 748 nm 780 nmtetramethylindotricarbocyanine Iodide (Dye 232)1,1′,3,3,3′,3′-hexamethylindodicarbocyanine DVD 638 nm 658 nm Iodide(Dye 233) DTP CD 800 nm(33 ps) 848 nm (Dye 239) HITC Iodide CD 742nm(1.2 ns) 774 nm (Dye 240) IR P302 CD 740 nm 781 nm (Dye 242) DTTCIodide CD 755 nm 788 nm (Dye 245) DOTC Iodide DVD 690 nm 718 nm (Dye246) IR-125 CD 790 nm 813 nm (Dye 247) IR-144 CD 750 nm 834 nm (Dye 248)

Having thus described certain embodiments in the present invention,various alterations, modifications, and improvements will readily occurto those skilled in the art. Such alterations, modifications, andimprovements are intended to be within the spirit and scope of theinvention. Accordingly, the foregoing description is by way of exampleonly, and is not intended to be limiting. The invention is limited onlyas defined in the following claims and the equivalents thereof.

1. A recordable optical data storage medium comprising: a substrateincorporating a data recording and playback structure configured toprovide for the recording and playback of optical data; a lightsensitive material, characterized in displaying at least two distinctoptical states to an optical reader, placed on said substrate in apattern associated with said data recording and playback structure; saidpattern of said light sensitive material configured to provide an uniquecode as read by optical reader.
 2. The recordable optical data storagemedium, in accordance with claim 1, wherein the said light sensitivematerial is configured to provide for the reading of the unique codewhen the said light sensitive material is in one of said at least twodistinct optical states.
 3. The recordable optical data storage medium,in accordance with claim 1, wherein the said light sensitive material isconfigured to provide for the reading of said unique code by detectingdifference between subsequent readings of the same portion of said lightsensitive material.
 4. The recordable optical data storage medium inaccordance with claim 1 wherein said substrate is a CD.
 5. Therecordable optical data storage medium in accordance with claim 1wherein said substrate is a DVD.
 6. A method for distributing data filescomprising: providing a recordable optical storage medium comprising asubstrate incorporating a data recording and playback structureconfigured to provide for the recording and playback of optical data,said recordable optical storage medium comprising a light sensitivematerial placed on said substrate, in a pattern, and associated withsaid data recording and playback structure, said material characterizedas displaying at least two distinct optical states to an optical reader,said pattern of said light sensitive material configured to provideunique code as read by optical reader; remotely providing said datafiles to said recordable storage medium, wherein said data files are inencoded form that requires said unique code to be read with an opticalreader, for said encoded data files to be decoded; and providinginstructions necessary to decode said data files using said unique code7. The method for distributing data files, in accordance with claim 6,where the INTERNET is used to provide said data files in encoded form.8. The method for distributing data files, in accordance with claim 6,where said data files are selected from the group consisting of movies,software and music.
 9. The method for distributing data files, inaccordance with claim 6, wherein the recordable optical data storagemedium is a CD.
 10. The method for distributing data files, inaccordance with claim 6, wherein the recordable optical data storagemedium is a DVD.